UPDATE:
So, some permissions cannot be gained, even are in manifest and asked.
In my situation with Android 9 and TV Boxes i had managed to give access to DUMP permission via shell.
pm grant com.test.app android.permission.DUMP
Also by root i did the rest, to give access to hdmi-cec ( /sys/class/cec/cmd ) access to all apps.
For now my issues are solved. All works fine (for now 
)